Sixteen regional leaders attending the summit in Phnom Penh also threw their weight behind a new set of talks, known as the Regional Comprehensive Economic Partnership (RCEP).

The pact will be based on existing trade deals in the region, including the free-trade agreement between Australia, New Zealand and the 10 ASEAN nations.

Trade officials are keen to conclude the talks by 2015.

Ms Gillard said both the TPP and RCEP were important to reaching the long-term goal of creating the world's largest free-trade zone in the Asia-Pacific region.

"Australia is a great trading nation and freer trade arrangements mean more jobs for Australians," Ms Gillard told reporters in Phnom Penh on Tuesday.

Speaking during his talks with Chinese Premier Wen Jiaboa, which included discussions on trade and tensions in the South China Sea, Mr Obama said he was ambitious to open up trade in the region.

"As the two largest economies in the world, we have a special responsibility to lead the way in ensuring sustained and balanced growth, not only here in Asia, but globally," Mr Obama said.

Mr Wen said China was committed to enhancing business co-operation and engaging in "large-scale co-operation" in terms of economic ties.

Ms Gillard, who also discussed trade and security issues in a meeting with Mr Wen, told reporters Australia was not taking sides on the disputed territories in the South China Sea, but backed the future adoption of a code of conduct for dealing with conflicts.

ASEAN leaders broke up their summit held just before the EAS without agreeing on the code of conduct, but backing further talks.

A minority of nations including Vietnam and the Philippines argued the issue needed to be dealt with multilaterally, but China argued it was working to resolve individual issues on a bilateral basis.

Ms Gillard also announced Australia would fund a $50 million program to combat people trafficking and fight malaria.

Asked whether Mr Obama had offered her advice on how to beat a conservative party, Ms Gillard said: "We will get about doing that in our own way."